Boston gas explosions injure three

Three people have been left injured after dozens of gas explosions rocked communities north of Boston.

Gas explosions in the towns of Lawrence, North Andover and Andover left several buildings engulfed in flames, although firefighters have now extinguished 35 fires, according to CNN.

According to the Massachusetts State Police at least 70 buildings required attendance form emergency services due to fire, explosions or gas odours.

Large swathes of the motorway have been closed and residents of South Lawrence forced to evacuate their homes.

Customers of energy company Columbia Gas have also been asked to evacuate their homes.

Boston 25 News said on Twitter an entire town is being evacuated.

"North Andover Board of Selectman tells Boston 25 News they are trying to evacuate the entire town," it said.

"What we know is that there have been multiple explosions, multiple fires that are happening across the city," Lawrence Mayor Dan Rivera told WBZ.

"What we need folks to do is that if it's happening in your home, you have a funny smell, just evacuate, come out to the street."

Police say it is too early to say what caused the gas main to explode.

"Numerous evacuations of neighborhoods where there are gas odors are underway," the Massachusetts State Police wrote on Twitter.

"Far too early to speculate on cause. Joint investigation will be conducted when situation is stabilized."